学步园

     三星已经对JPEG解码做好了驱动，应用通过调用JPEG解码的API函数，从而调用JPEG驱动，驱动通过6410的内部硬件解码，将JPEG格式的数据解码成YUV格式的数据，然后将YUV格式转化成RGB，通过LCD显示出来。

     在三星提供的BSP包中，有文件S3C6410_WinCE6.0_WM6.0_JPEG_API.pdf，里面详细介绍了JPEG的使用方法。另外，三星还做了个JPEG的例子，在BSP包中路径为：E:/WINCE600/PLATFORM/SMDK6410/SAMPLES/JPEG，直接在PB6.0中编译生成*.exe文件，即可在6410的平台上运行。

     JPEG的解码测试代码如下：

void TestDecoder()<br /> {<br /> char *InBuf = NULL;<br /> char *OutBuf = NULL;<br /> char *OutPhyBuf = NULL;<br /> char *OutRGBBuf = NULL;<br /> char *OutRGBPhyBuf = NULL;<br /> FILE *fp;<br /> FILE *CTRfp;<br /> UINT32 fileSize;<br /> UINT32 streamSize;<br /> void *handle;<br /> INT32 width, height, samplemode;<br /> JPEG_ERRORTYPE ret;<br /> char outFilename[128];<br /> char inFilename[128];<br /> BOOL result = TRUE;<br /> // int i;//added by lqm.<br /> #if (FPS == 1)<br /> INT32 decodeTime;<br /> #endif<br /> DWORD startTime;<br /> RETAILMSG(1,(L"------------------------Decoder Test Start ---------------------/n"));<br /> //////////////////////////////////////////////////////////////<br /> // 0. Get input/output file name //<br /> //////////////////////////////////////////////////////////////<br /> //CTRfp = fopen(CTRL_FILE_NAME, "rb");// 解码时，CTRL_FILE_NAME = "fname_dec.txt"<br /> CTRfp = fopen("//Nand-disk//JPEG//fname_dec.txt", "rb");<br /> if(CTRfp == NULL)<br /> {<br /> RETAILMSG(1,(L"file open error : %s/n", CTRL_FILE_NAME));<br /> return;<br /> }<br /> do<br /> {<br /> memset(outFilename, 0x00, sizeof(outFilename));// 将数组里面的128个数据全部填0<br /> memset(inFilename, 0x00, sizeof(inFilename));<br /> fscanf(CTRfp, "%s", inFilename);//将*CTRfp指向的文件CTRL_FILE_NAME里的第n行数据读到inFilename[]数组<br /> if(inFilename[0] == '#')//文件以"#"表示结束，当读到"#"时表示解码结束<br /> {<br /> RETAILMSG(1,(L"------------------------Decoder Test Done ---------------------/n"));<br /> fclose(CTRfp);<br /> return;<br /> }<br /> fscanf(CTRfp, "%s", outFilename);//将*CTRfp指向的文件CTRL_FILE_NAME里的第n+1行数据读到outFilename[]数组<br /> if(inFilename == NULL || outFilename == NULL)<br /> {<br /> RETAILMSG(1,(L"read file error/n"));<br /> RETAILMSG(1,(L"------------------------Decoder Test Done ---------------------/n"));<br /> fclose(CTRfp);<br /> return;<br /> }<br /> // 为什么下面的打印信息是隔一个字符打印一个?<br /> RETAILMSG(1,(L"inFilename : %s /noutFilename : %s/n", inFilename, outFilename));<br /> //////////////////////////////////////////////////////////////<br /> // 1. handle Init //<br /> //////////////////////////////////////////////////////////////<br /> #if (FPS == 1)<br /> decodeTime = GetTickCount();//读取以毫秒为单位的计算机启动后经历的时间间隔。<br /> #endif<br /> handle = SsbSipJPEGDecodeInit();<br /> #if (FPS == 1)<br /> decodeTime = GetTickCount() - decodeTime;<br /> RETAILMSG(1,(L"Initialization Time : %d /n", decodeTime));<br /> #endif<br /> if(handle == NULL)<br /> {<br /> RETAILMSG(1,(L"Decoder Init failed/n"));<br /> break;<br /> }<br /> //////////////////////////////////////////////////////////////<br /> // 2. open JPEG file to decode //<br /> //////////////////////////////////////////////////////////////<br /> fp = fopen(inFilename, "rb");// 打开inFilename数组中指定的文件<br /> if(fp == NULL)<br /> {<br /> result = FALSE;<br /> RETAILMSG(1,(L"file open error : %s/n", inFilename));<br /> break;<br /> }<br /> // 以下三句用于计算文件的长度<br /> // 在这里用于计算打开的JTAG图像文件的大小(byte)<br /> fseek(fp, 0, SEEK_END);//把文件指针指向文件尾部<br /> fileSize = ftell(fp);//读取当前指针位置偏离文件头部的字节数<br /> fseek(fp, 0, SEEK_SET);//把文件指针指向文件首部<br /> RETAILMSG(1,(L"filesize : %d/n", fileSize));<br /> //////////////////////////////////////////////////////////////<br /> // 3. get Input buffer address //<br /> //////////////////////////////////////////////////////////////<br /> InBuf = SsbSipJPEGGetDecodeInBuf(handle, fileSize);<br /> if(InBuf == NULL){<br /> RETAILMSG(1,(L"Input buffer is NULL/n"));<br /> result = FALSE;<br /> break;<br /> }<br /> RETAILMSG(1,(L"inBuf : 0x%x/n", InBuf));<br /> //////////////////////////////////////////////////////////////<br /> // 4. put JPEG frame to Input buffer //<br /> //////////////////////////////////////////////////////////////<br /> fread(InBuf, 1, fileSize, fp);//把fp指向的图像文件的数据存入输入缓冲区<br /> fclose(fp);//释放打开的图像文件</p> <p> //////////////////////////////////////////////////////////////<br /> // 5. Decode JPEG frame //<br /> //////////////////////////////////////////////////////////////<br /> #if (FPS == 1)<br /> decodeTime = GetTickCount();<br /> #endif<br /> ret = SsbSipJPEGDecodeExe(handle);//JPEG格式解码<br /> #if (FPS == 1)<br /> decodeTime = GetTickCount() - decodeTime;<br /> RETAILMSG(1,(L"decodeTime : %d ms/n", decodeTime));//打印解码所花的时间<br /> #endif<br /> if(ret != JPEG_OK){<br /> RETAILMSG(1,(L"Decoding failed/n"));<br /> result = FALSE;<br /> break;<br /> }<br /> //////////////////////////////////////////////////////////////<br /> // 6. get Output buffer address //<br /> //////////////////////////////////////////////////////////////<br /> OutBuf = SsbSipJPEGGetDecodeOutBuf(handle, &streamSize);<br /> if(OutBuf == NULL){<br /> RETAILMSG(1,(L"Output buffer is NULL/n"));<br /> result = FALSE;<br /> break;<br /> }<br /> printD("OutBuf : 0x%x streamsize : %d/n", OutBuf, streamSize);<br /> //////////////////////////////////////////////////////////////<br /> // 7. get decode config. //<br /> //////////////////////////////////////////////////////////////<br /> SsbSipJPEGGetConfig(JPEG_GET_DECODE_WIDTH, &width);<br /> SsbSipJPEGGetConfig(JPEG_GET_DECODE_HEIGHT, &height);<br /> SsbSipJPEGGetConfig(JPEG_GET_SAMPING_MODE, &samplemode);<br /> RETAILMSG(1,(L"width : %d height : %d samplemode : %d/n/n", width, height, samplemode));<br /> //////////////////////////////////////////////////////////////<br /> // 8. write output file //<br /> //////////////////////////////////////////////////////////////<br /> #if (TEST_DECODE_OUTPUT_YCBYCR == 1)<br /> DecodeFileOutYCBYCR(OutBuf, streamSize, outFilename); // YCBYCR interleaved<br /> #elif (TEST_DECODE_OUTPUT_YUV422 == 1)<br /> DecodeFileOutYUV422(OutBuf, streamSize, outFilename); // yuv422 non-interleaved<br /> #elif (TEST_DECODE_OUTPUT_RGB16 == 1) //RGB16<br /> OutPhyBuf = SsbSipJPEGGetDecodeOutPhyBuf(handle);<br /> OutRGBPhyBuf = SsbSipJPEGGetRGBPhyBuf(handle, LCD_X, LCD_Y);<br /> if(ConvertYCBYCRToRGB((int)OutPhyBuf, width, height,<br /> POST_SRC_YUV422_CRYCBY,<br /> (int)OutRGBPhyBuf, LCD_X, LCD_Y,<br /> POST_DST_RGB16) == FALSE){<br /> RETAILMSG(1,(L"ConvertYCBYCRToRGB error/n"));<br /> result = FALSE;<br /> break;<br /> }<br /> OutRGBBuf = SsbSipJPEGGetRGBBuf(handle, LCD_X, LCD_Y);<br /> DecodeFileOutRGB16ToPPM(OutRGBBuf, LCD_X, LCD_Y, outFilename);<br /> #elif(TEST_DECODE_OUTPUT_LCD == 1)<br /> OutPhyBuf = SsbSipJPEGGetDecodeOutPhyBuf(handle);//获得解码输出缓冲的物理地址<br /> OutRGBPhyBuf = SsbSipJPEGGetRGBPhyBuf(handle, LCD_X, LCD_Y);//获得解码输出缓冲的物理地址<br /> startTime = GetTickCount();<br /> if(ConvertYCBYCRToRGB((int)OutPhyBuf, width, height,<br /> POST_SRC_YUV422_CRYCBY,<br /> (int)OutRGBPhyBuf, LCD_X, LCD_Y,<br /> POST_DST_RGB16) == FALSE){<br /> RETAILMSG(1,(L"ConvertYCBYCRToRGB error/n"));<br /> result = FALSE;<br /> break;<br /> }<br /> RETAILMSG(1,(L"converting time : %d/n/n", GetTickCount() - startTime));<br /> RETAILMSG(1,(L"/n/n This image will be disappeared after %d seconds....../n/n", DISPLAY_TIME));<br /> DisplayJPEG((int)OutRGBPhyBuf, LCD_X, LCD_Y, LCD_X, LCD_Y, DISPLAY_TIME);<br /> #endif<br /> //////////////////////////////////////////////////////////////<br /> // 9. finalize handle //<br /> //////////////////////////////////////////////////////////////<br /> SsbSipJPEGDecodeDeInit(handle);<br /> Sleep(5);<br /> }<br /> while(1);<br /> if(result == FALSE)<br /> {<br /> SsbSipJPEGDecodeDeInit(handle);<br /> }<br /> fclose(CTRfp);<br /> RETAILMSG(1,(L"------------------------Decoder Test Done ---------------------/n"));<br /> }

    这些代码会调用JPGApi.c中的若干API函数，在API函数中可以看到他们开始打开驱动，然后逐个调用JPEG驱动了。例如，解码JPEG的函数如下：

JPEG_ERRORTYPE SsbSipJPEGDecodeExe(void *openHandle)<br /> {<br /> int ret;<br /> printD("API :: jCtx->decParam->fileSize : %d/n", jCtx->decParam->fileSize);<br /> if(jCtx->decParam->decType == JPG_MAIN){<br /> ret = DeviceIoControl(openHandle, IOCTL_JPG_DECODE, NULL,<br /> 0, NULL, 0,<br /> (PDWORD)jCtx->decParam, NULL);<br /> if(ret == 0){<br /> RETAILMSG(1, (TEXT("API :: IOCTL_JPG_DECODE failed/r/n")));<br /> return JPEG_FAIL;<br /> }<br /> printD("API :: decParam->width : %d decParam->height : %d/n", jCtx->decParam->width, jCtx->decParam->height);<br /> printD("API :: streamSize : %d/n", jCtx->decParam->dataSize);<br /> }<br /> else{<br /> // thumbnail decode, for the future work.<br /> }<br /> return JPEG_OK;<br /> }

    驱动三星也已经都做好了，这里就不一一把代码贴上来了。

    值得注意的是，将该例子生成的可执行文件拷到WINCE平台运行的同时，还要将测试图片，记录测试图片路径的文本文件一并拷到WINCE平台，注意拷备的最终路径，要和程序中代码严格对应，否则无法打开图片文件或是文本文件。

    存放的图片路径如下：

    E:/WINCE600/PLATFORM/SMDK6410/SAMPLES/JPEG/test/testVectors

    存放的广本文件的路径如下：

    E:/WINCE600/PLATFORM/SMDK6410/SAMPLES/JPEG/test/fname_dec.txt